Dynamic response history analysis

The 2003 NEHRP Recommended Provisions (BSSC 2004) specify procedures for ncmtinear static analysis and nonlinear dynamic (response-history) analysis. The nonlinear static analysis procedure is similar to the ELF procedure, in that the pushover capacity curve is used to define the nonlinear behavior of the structure. However, in the nonlinear static analysis procedure, the actual nonlinear force-displacement relation is used, rather than an idealized elastoplastic curve. In addition, since actual pushover strength is known from the nonlinear pushover analysis, the force reduction for design of the seismic-force-resisting system is based on overstrength alone with no additional reduction (Symans et al. 2008). 

Nonlinear dynamic analysis Nonlinear response history analysis Time history analysis... 

Both deterministic and stochastic simulations can be used for response-history dynamic analysis, but only stochastic simulations can be utilized for stochastic dynamic (i.e., random vibration) analysis, because the latter analysis method requires a random process model of the earthquake ground motion. Synthetic ground motions are particularly useful for nonlinear dynamic analysis due to the scarcity of recorded motions for large-magnitude earthquakes that are capable of causing nonlinear responses. Two approaches are available for nonlinear dynamic analysis of structures subjected to earthquakes (1) nonlinear response-history analysis by the use of a selected set of ground motion time series and (2) nonlinear stochastic dynamic analysis by the use of a stochastic representation of the ground motion. 

Nonlinear dynamic analysis is undoubtedly the most realistic and accurate analysis method available. It is also referred as nonlinear time history analysis, nonlinear response history analysis, or according to ASCE 41-06 (2007) as nonlinear dynamic procedure (NDP). Earthquake loading is taken into consideration as a natural or a synthetic ground motion on a structural model... 

The dynamic methods used are a modal analysis with a spectrum as an input and a space-time history analysis which needs one or more accelerograms for inputs. Analyses of the first type are the most common ones the second type is used in particular cases or for the accurate study of the response of a plant component placed at a specific place in a structure. 

Rizos, D.C. Sc Loya, K.G. 2002. Dynamic and seismic analysis of foundations based on free field B-Spline characteristic response histories. Journal of Engineering Mechanics 128 438—448. 

The treatment of uncertainties requires the use of probabilistic methods, estimating the probability of exceeding response targets for the different performance requirements, for example, on an annual basis. The dynamic structural responses are highly nonlinear, and their time history must be found by numerical (e.g., finite elements) analysis for the duration of the earthquake. In a thorough analysis, the nonlinearity of the response is further increased when the interactions between the structure and the foundations are included. It is not possible to establish an explicit relationship between the intervening variables and the dynamic responses, and results can only be obtained in a discrete manner, given specific values of the structural variables and a particular earthquake record. Reliability calculations depend on simulations... 

The seismic input is represented by the acceleration response spectrum included in the codes and the displacement spectrum or with a set of accelerograms. The type of analysis is static, dynamic, or response history. The stiffness that is used to calculate the maximum displacement demand is the equivalent pre-yielding stiffness or the equivalent secant stiffness, usually obtained based on the pushover analysis. This variety of solutions can result in a different estimation of the response. In section Different Applications of the Inelastic Pushover-Based Analysis, Adopted in the (Pre)Standards and Guidelines, those solutions (methods), which are adopted in Eurocode 8/3 (CEN 2005), ATC-40 (ATC 1996), and EEMA-356 (ASCE 2000), the recommended modifications in EEMA-440 (ATC FEMA 2005), and the displacement-based method, included in the NZSEE (2006), are presented. They were selected since they illustrate many of the basic concepts that are currently in use. 

Lin et al. (2013 a) for the first time used the term conditional spectrum which was used to represent an analytical distribution of response spectra in the manner described here. The CS builds upon the CMS (which focuses on the mean) and includes a measure of the variance in addition to the mean. Figure la depicts the analytical distribution of the conditional spectrum with conditional mean spectrum as the thick solid line as well as conditional mean +/— conditional standard deviation as the thick dashed lines. Lin et al. (2013b, c) utilized the conditional spectrum to select ground motions for nonlinear dynamic analysis (also known as response history... 

The current trend in seismic design of dams is to conduct linear or nonlinear time-history analysis to obtain dynamic response of dam to earthquake loads. Time-history analysis of dam requires input ground motion time histories (acceleration, velocity, and displacement). 

The glass transition temperature can be measured in a variety of ways (DSC, dynamic mechanical analysis, thermal mechanical analysis), not all of which yield the same value [3,8,9,24,29], This results from the kinetic, rather than thermodynamic, nature of the transition [40,41], Tg depends on the heating rate of the experiment and the thermal history of the specimen [3,8,9], Also, any molecular parameter affecting chain mobility effects the T% [3,8], Table 16.2 provides a summary of molecular parameters that influence the T. From the point of view of DSC measurements, an increase in heat capacity occurs at Tg due to the onset of these additional molecular motions, which shows up as an endothermic response with a shift in the baseline [9,24]. 

The characterization of reactive intermediate, flee radical has been one of the most important challenges for the scientist in the history of chemistry. In early times, MS has appeared as a direct method to study radical intermediates due to its irmnediate response in the analysis. Among the variorrs original methods developed in the prrrpose of detecting and characterizing free radicals in dynamic chemical systems such as plasmas and combustion, the ion attachment mass spectrometry... 

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